Randell, D. A., Cui, Z. and Cohn, A. G.: 1992, "A spatial logic based on regions and connection," Proc. 3rd Int. Conf. on Knowledge Representation and Reasoning, Morgan Kaufmann, San Mateo, pp. 165-176. Available at: https://www.dpi.inpe.br/gilberto/references/cohn_rcc.pdf http://www.ontologyrepository.com/CommonCoreOntologies/Mid/GeospatialOntology has spatial part y has_spatial_part x iff x, y, z, and q are instances of Immaterial Entity, such that for any z connected with x, z is also connected with y, and q is connected with y but not connected with x.